Ophthalmic instruments



May 5, 1964 c. H. KEELER OPHTHALMIC INSTRUMENTS 2 Sheets-Sheet 1 FiledSept. 11, 1961 FIG.9.

FIG.10.

R O T N E V N T hdewvh ATTORNEYS May 5,1964

C. H. KEELER OPHTHALMIC INSTRUMENTS 2 Sheets-Sheet 2 Filed Sept. 11,1961 l NV ENTO R C zar [es/ven *jlf eeler- AT TORN EYS United StatesPatent 3,131,695 OPHTHALMIC INSTRUMENTS Charles Henry Keeler, SeftonLawn, Clewer Green, Windsor, England Filed Sept. 11, 1961, Ser. No.137,214 Claims priority, application Great Britain Sept. 12, 1960 10(Ilaims. (Cl. 128-395) This invention relates to ophthalmoscopes. It isan object of the invention to provide an ophthalmoscope which, inaddition to being capable of use in the same manner as a conventionalophthalmoscope can also be employed to perform certain additionalfunctions notably the detection and treatment of eccentric fixation ofthe macula of a patient. Hitherto, it has been necessary to employ twoor more separate instruments in carrying out pleoptics treatment, viz.,one instrument for diagnosis and another to produce a maculaafter-image. The present invention enables both phases of detection andtreatment of eccentric fixation to be undertaken with a singleinstrument.

According to the present invention there is provided an ophthahnoscopeincorporating a compound graticule holder adapted to be detachablysecured to the focusing column of the instrument, said holder comprisinga stationary portion containing a first graticule for determiningeccentric fixation of the macula of the eye of a patient and a slidableportion containing a second graticule adapted automatically to bedisplaced to a position in which it is superimposed on said firstgraticule, means being provided whereby simultaneously with said displacement the extra-macula retina of the eye can be subjectedautomatically to continuous or intermittent illumination ofpredetermined intensity and time duration to produce a maculaafter-image.

The invention is illustrated by way of example in the accompanyingdrawings in which:

FIGURE 1 is a perspective view showing an ophthalmoscope according tothe invention held by an operator during treatment of a patient.

FIGURE 2 is a fragmentary perspective view showing the compound slidelocated over the focusing tube of the ophthalmoscope and the maculaocclusion graticule being partially inserted into position within theslide.

FIGURE 3 is a fragmentary perspective view showing the macula occlusiongraticule fully inserted into the slide and locked in position.

FIGURE 4 is a fragmentary perspective view showing the macula occlusiongraticule pulled outwardly to energise the automatic mechanism and thusexpose the graticule, located in the stationary portion.

FIGURE 5 is a fragmentary perspective view showing a red-free graticuleabout to be inserted into a peripheral slot in the wall of theophthahnoscope beneath the compound slide.

FIGURE 6 is a fragmentary perspective view showing the red-freegraticule located in the operative position.

FIGURE 7 is a plan view, drawn to an enlarged scale, showing a movable.graticule holder.

FIGURE 8 is a sectional side view taken on the line 8-8 of FIGURE 7.

FIGURE 9 is a plan view showing a star graticule which remainspermanently in position within the graticule holder.

FIGURE 10 is a plan view showing a red-free graticule.

FIGURE 11 is a side view partly in section, and drawn to an enlargedscale, showing a compound slide according to the invention, and

FIGURE 12 is a cross-sectional view taken on the line 1212 of FIGURE 11.

Referring to the drawings the ophthalmoscope is of known form such asthat described in United Kingdom specification No. 665,531 anddesignated generally by the reference numeral 1. The ophthalmoscopeincorporates a focusing tube 2 which is adjustable by means of thefocusing button 3 (FIGURES 5 and 6). The focusing tube 2 is adapted tosupport a compound graticule holder in accordance with the invention.The graticule holder comprises a fiat body portion 4 having at one end acircular aperture 5 containing a star graticule 6 which is fixedlylocated therein. The body portion 4 is formed with an elongated opening7 on its upper face, the opening 7 communicating with the aperture 5(see FIGURE 12). The side walls of the opening 7 are formed with adovetail groove 8. Another graticule holder 9 is arranged for slidingmovement with respect to the body portion 4, the holder 9 havinginclined sides 10 which interlock with the dovetail groove 8 in theelongated opening 7 in the body portion 4. The holder 9 is formed at itsforward end with an aperture 11 containing an occluder graticule 12having a central opaque area 13 (shown as a black spot). The slidinggraticule holder 9 has a lateral slot 14 therein, for a purposehereinafter described, and is also provided with a projection 15 formanipulation purposes. The body portion 4 is formed with a longitudinalaperture 16 (FIGURES 11 and 12) within which is slidable a tubularplunger 17 which encloses a coil spring 18 (FIGURE 12) fixedly attachedat one end to the outer end of the plunger and at the opposite end to ascrew 19. The forward end of the plunger 17 is formed with a peripheralgroove 20 engageable by a spring-pressed detent 21 (FIGURES 11 and 12)when the plunger 17 is pulled outwardly by means of a projection 22 onthe outer end of the plunger 17, the detent being released fromengagement with the groove 20 on the plunger 17 through the medium of aBowden wire control 23. The plunger 17 is rotatable within the aperture16 in the body portion 4 so that the projection 22 assumes a position inwhich it lies in a horizontal plane so as to permit the graticule holder9 to be slid into position in the body portion. Thereafter, the plunger17 is rotated so that the projection 22 is in a vertical position inwhich position it enters the slot '14 in the movable graticule holder 9,thus causing. the plunger 17 and consequently the holder 9 to beadvanced or retracted within the body 4 as desired. The upper face ofthe movable graticule holder 9 carries an electric contact 24 which isadapted to effect engagement with contacts 25 and 26 carried by a blockof insulating material 27 mounted on the upper surface of the bodyportion 4, the contacts 25 and 26 being connected to an electrictransformer (not shown) housed in a separate container (not shown)incorporating a rheostat control which is adjustable to provide up to amaximum current of about 1 amp. The said container houses a time switch,a graduated dial being provided on the top of the container whereby theswitch can be set to provide illumination of predetermined timeduration. To enable the compound slide to be fixedly attached to thefocusing tube 2 a set-screw 28 is provided. The ophthalmoscope is provided with a peripheral slot 29 which accommodates a graticule having ared-free, i.e. clear, aperture 30 therein and carrying a projecting arm31 which is engageable with the trigger 32 of the Bowden wire control.

In using the instrument for the diagnosis of eccentric fixation andafter-image treatment of a patient, the size of spot occluder graticuleis selected and inserted into the focusing tube 2 of the ophthalmoscope.The sliding gnaticule holder 9 is then inserted into the elongatedopening 7 in the body portion 4 and urged inwards as far as it will go,the projection 22 on the plunger 17 being turned upwardly into thevertical position when it entered into the slot 14 in the holder 9, thuscoupling the plunger 17 and the holder 9 together. The holder 9 PatentedMay 5., 1964- is then pulled outwardly until the detent 21 has enteredthe peripheral groove 20 in the plunger 17 thereby exposing the lstargraticule 6 to the light beam. The redfree slide is then inserted intothe slot 29 so that the arm 30 is engaged by the trigger 32 of theBowden control. The transformer rheostat control and time switch are nowset to alford the required conditions when operated. The star graticulewhich is permanently in position is now focused onto the macula of theeye of the patient and the degree of eccentricity of fixationdetermined. The Bowden wire control is then actuated causing thered-free slide to be removed from the light path and simultaneously thegraticule holder 9 will be released so that it moves forward and thespot occluder '13 is superimposed on the star graticule 6. The electriccontacts on the graticule holder 9 and the block 27 respectively willeffect engagement thus completing the electrical circuit and causing anintense w te light to be projected onto the eXtra-macula retina, therebydazzling the area in which retinoception is taking place, but, at thesame time protecting the macula and hence stimulating it. Theafter-image thereby produced can be prolonged or intensified by theconventional flashing light technique, for which purpose an alternatorunit incorporated in the electrical circuit can be brought intooperation upon actuating a suitable switch. The effect is to inhibit thefalse macula and to stimulate the eye to correct foveal fixation.

The spot occluder graticule in the holder 9 can, if desired, besubstituted by a red-free filter (FIGURE 10) having a clear centralaperture which the operator centres on the fovea, the alternator unitbeing brought into operation to impart intermittent light flashes to thefoveal area.

I claim:

1. In an ophthalmoscope having a focusing tube, a compound graticuleholder detachably mounted on said focusing tube, said holder including abody portion, a tfirst graticule for determining eccentric fixation ofthe macula of the eye of a patient, said first graticule being disposedin said body portion, a slidable member slidably disposed in saidholder, a second graticule disposed in said slidable member, meansoperatively engaging said slid-able member to maintain said secondgraticule in a position remote from said first graticule, meansautomatically displacing said slidable member to superimpose said secondgraticule over said first graticule, and means operated simultaneouslywith the displacement of said slidable member to subject theextra-macula retina of the eye to continuous or intermittentillumination of predetermined intensity and time duration to produce amacula after-image.

2. An ophthahnoscope according to claim 1, wherein said body portioncomprises a flat body having a circular aperture therein in which saidfirst graticule is fixedly mounted, said fiat body having an elongatedopening on the upper face thereof which opening communicates with saidaperture, the side walls of said opening being formed with a dovetailgroove.

3. An ophthalmo'scope as claimed in claim 1 wherein said secondgraticule is a red-free graticule.

4. An ophthalmoscope according to claim 2, wherein said slidable memberis formed with an aperture at its forward end containing said secondgraticule, the sides of said slidable member being inclined so as tointerlock with the grooves in the side walls of the elongated opening insaid fiat body.

5. An ophthalmoscope according to claim 1, wherein said engaging meansincludes a longitudinal bore formed in said body portion which receivesa spring-actuated plunger carrying means whereby said slidable membercan be coupled thereto and advanced or retracted with respect to thebody portion.

6. An ophthalmoscope according to claim 5 wherein the forward end ofsaid plunger is formed with a peripheral groove, a spring-pressed detentdisposed in said body portion to engage said groove when the plunger isin the fully advanced position, means being provided for releasing saiddetent from engagement with said groove to cause said slidable portionto be retracted to superimpose the second graticule over the firstgraticule.

7. An ophthalmoscope according to claim 1, wherein the slidable membercarries an electric contact, contacts disposed on a member carried bysaid body portion and engageable with said electric contact so as to beenergised by electric current means controlled by a rheostat to providethe illumination of predetermined intensity and time duration.

8. An ophthalmoscope as claimed in claim 7, wherein means areoperatively connected to :said electric current means to prolong orintensify the after-image by intermittent light flashes.

9. An ophthalrnoscope according to claim 1, wherein said first graticuleis a star graticule and said second graticule is a spot occludergraticule.

10. An ophthalmoscope according to claim 1, wherein a red-free slide isdisposable within the illumination path, and means operatively connectedto said red-free slide to automatically displace same when the secondgraticule has been superimposed over the first graticule.

References Cited in the file of this patent UNITED STATES PATENTS1,698,124 De Zeng Jan. 8, 1929 2,821,977 Ga ssman Feb. 4, 1958 2,986,068Mandaville May 30, 1961

1. IN AN OPHTHALMOSCOPE HAVING A FOCUSING TUBE, A COMPOUND GRATICULEHOLDER DETACHABLY MOUNTED ON SAID FOCUSING TUBE, SAID HOLDER INCLUDING ABODY PORTION, A FIRST GRATICULE FOR DETERMINING ECCENTRIC FIXATION OFTHE MACULA OF THE EYE OF A PATIENT, SAID FIRST GRATICULE BEING DISPOSEDIN SAID BODY PORTION, A SLIDABLE MEMBER SLIDABLY DISPOSED IN SAIDHOLDER, A SECOND GRATICULE DISPOSED IN SAID SLIDABLE MEMBER, MEANSOPERATIVELY ENGAGING SAID SLIDABLE MEMBER TO MAINTAIN SAID SECONDGRATICULE IN A POSITION REMOTE FROM SAID FIRST GRATICULE, MEANSAUTOMATICALLY DISPLACING SAID SLIDABLE MEMBER TO SUPERIMPOSE SAID SECONDGRATICULE OVER SAID FIRST GRATICULE, AND MEANS OPERATED SIMULTANEOUSLYWITH THE DISPLACEMENT OF SAID SLIDABLE MEMBER TO SUBJECT THEEXTRA-MACULA RETINA OF THE EYE TO CONTINUOUS OR INTERMITTENTILLUMINATION OF PREDETERMINED INTENSITY AND TIME DURATION TO PRODUCE AMACULA AFTER-IMAGE.